Whistle Rocket Discussion
WARNING AND DISCLAIMER: If you are underage, then consult with your parents or guardians before attempting any of this. You are on your own - I'm not responsible for your actions or harm you may bring to others because of your actions. Making the items described below can result in injury or death to you or people in your vicinity. Some things mentioned here may be illegal to make in your city, county, state, or country so check the laws that apply to you before you attempt anything described here. These notes are not complete on purpose. If you are reading them and new to pyrotechnics, then you are making a mistake. Stop now - this page is not for you. Get a beginning book on fireworks (see Skylighter or American Fireworks News (very quick shipping) for a start) and read up. You can't make any of this work without more information so read up or join a club or ask someone to help you.
Every now and then you run into a posting on the newsgroups or Passfire that really has a lot going for it. The following is such a quote. Steve La Duke* was answering a question about whistle rockets on Passfire and contributed the following - he kindly gave me permission to record it here:
The Original Question that Steve was Answering
"As I will make my own tooling (for a whistle motor) tonight I am wondering about the dimensions of the core. Is there a specified grain to core ratio for the width and depth of the core? I'm making 3/4'' id rockets."
"The ideal size for a whistle spindle will vary, depending on the type of perchlorate used in the fuel. It would also depend on whether you are using benzoate or salicylate in the fuel. The perfect length to make your spindle and diameter of the base would be around 2-1/2 inches long by 1/4 inch in diameter."
"Once the tooling is made, then you should be able to make salicylate whistle rockets with a real kick. The fuel to use is 76 perk, 23 sodium salicylate, 1 iron oxide or for more power, 1 part copperoxichloride and 2.5 parts Vaseline. I use melted Vaseline added to lacquer thinner to distribute the Vaseline through out the mix. Now the tweaking part comes into play. Press these motors to about 8000 psi. If they blow, then slow the fuel down by adding an extra part Vaseline to the next batch of fuel. I'm sure this dimension for the spindle will work so don't fret. You could also make a batch of fuel with more salicylate added to it. Say a mix of 70- 30-1-2.5. This will weaken the rocket but it will also slow it down and eliminate the possibility of CATOing. Or you could add more Vaseline to the original mix but no more the 4 parts Vaseline. If using benzoate for the fuel, use the same ratio of chems. I'm sure you won't have any problems with it. "
"Now, if you want to get fancy, just make up a strobe rocket spindle 3 inches long by .450 inches in dia. in the 3/4 inch dia. rocket. Now you have a spindle that can make 3 different rockets. One, a strobe rocket. Two, a mini long winded screamer and three, a powerful nozzled, hybrid fueled rocket. Three different rockets with the same tooling! To use it as LWS tooling, just press in 4 increments of salicylate whistle mix made to 76-23-1-2.5 and finish it with a whistle mix made from benzoate at the ratio of 64-32-1-5, which is perk, benzoate, iron oxide or copperoxichloride for more power and 5 parts Vaseline. A real kick-ass rocket that will impress anybody. "
"Then you can make the strobe rocket which I won't go into right now and then the hybrid rocket. Here you have to use a clay nozzle and to use that, you have to cut the angle of the first rammer to the required taper on the end. If you do this to the rammer, it won't affect the other motors that you make using it. I machine this angle to 45 degrees on the compound on the lathe. Then you have to make up some # 1 hybrid fuel which is 76-23-1-3-10. This is the standard whistle fuel using salicylate with the 10 being ball milled charcoal. Press the rocket all the way to 5/16 above the spindle with this fuel and then press in any other fuel you want that will give a nice tail. The total above the spindle should be at least 1 inch, depending on the delay you use. No clay is used above the spindle bulkhead. You may want to use more than 1 inch if necessary. Now, if you want a nice tail on the rocket and make it look like a black powder rocket,you have to make up a batch of 75-15-15-10-5 black powder. 75 parts potassium nitrate, 15 parts 36-40 mesh charcoal, 15 parts ball milled charcoal, 10 parts sulfur and 5 parts dextrin. This fuel is riced with water-alcohol and dried. This fuel is blended 50-50 by volume with the whistle mix stated above: 76-23-1-2.5 salicylate whistle fuel. I separately run each through a gravy strainer after it's dried and then blend them together dry. When this is pressed all the way to the top of your rocket and about 5/16 above the spindle, then you decide what you want for a tail. You can press anything you want for a tail and make sure you press at least 1 inch above the already pressed comp in the rocket. This rocket will easily lift a 3'' ball shell way beyond the perfect height. "
"All these rockets use a loading pressure of at least 8000 psi. Keep this in mind. Any questions and I will help."
Steve La Duke is a well-known rocketeer and helpful pyro. He has made several videos outlining his rocket motor construction techniques and you can get them from American Fireworks News (www.fireworksnews.com). You can usually meet him at the PGI conventions where he can be seen helping everyone at the rocket tent.